1. Field of the Invention
The invention relates to a fabricating method of an electron source device. More particularly, the invention relates to a fabricating method of an electron-emitting device.
2. Description of Related Art
The field emission display (FED) is a flat panel display technology similar to the conventional cathode ray tube (CRT) display. The principle of the FED is briefly described as follows. First, under the induction of an electric field, a plurality of juxtaposed electron source devices (on a cathode side) would emit electrons. Afterwards, the electrons are attracted and accelerated by an anode to bombard phosphor powder on the anode surface so as to emit a fluorescent light. Next, the fluorescent light would penetrate the anode, emit from a back surface thereof and display an image on the back surface of the anode (a front surface of a display panel).
According to different modes of electron emission, electron source devices can be classified into spindt, surface conduction electron-emitting device (SED), carbon nanotube (CNT), ballistic electron surface emitting display (BSD) and the like.
FIG. 1 schematically illustrates a top view of a conventional electron-emitting device. FIG. 2 schematically illustrates a cross-sectional view of FIG. 1 along the line A-A′. Referring to both FIGS. 1 and 2, an electron-emitting device 100 is constituted by a substrate 1, a first electrode 2, a second electrode 3 and a conductive thin film 4. The conductive thin film 4 has a slit 5 thereon.
Still referring to FIG. 2, a fabricating method of the electron-emitting device 100 has the following steps. First, a substrate 1 is provided. Next, a pair of a first electrode 2 and a second electrode 3 is formed on the substrate 1. Afterwards, the conductive thin film 4 is formed by an ink jet technique between the first electrode 2 and the second electrode 3. Then, a pulse voltage is applied between the first electrode 2 and the second electrode 3 so as to deoxidize the conductive thin film 4 and form the slit 5. The step is called a slit-forming process.
At this moment, since a width of the slit 5 is still within a sub-micrometer scale, electrons cannot be emitted from a surface of the conductive thin film 4 through a quantum tunnel effect when an electric field is applied. Therefore, an activation process has to be further performed to render the slit 5 as a nanometer scale slit.
More specifically, in the activation process, an organic gas containing carbon elements is induced to the slit 5. Furthermore, through application of a pulse voltage, the organic gas is decomposed into carbon elements and deposited on a periphery of the slit 5 in the sub-micrometer scale so that the slit 5 is further formed as the slit 5 in a nanometer scale.
In light of the above-mentioned, a conventional fabricating method of the conventional electron-emitting device 100 at least requires two steps—a slit-forming process and an activation process—so as to form a nanometer scale slit. Moreover, when forming the conductive thin film 4 by an ink-jet technology, a conductive solution containing nanometer scale conductive particles is required. Hence, an additional polishing process is required to prepare the conductive solution. In other words, the conventional fabricating method of the electron-emitting device 100 is complicated and a fabricating cost thereof is difficult to be reduced.
Particularly, when the conductive thin film 4 is formed by an ink jet technology, a complicated ink jet control mechanism is required as well. Therefore, if the electron-emitting devices 100 are fabricated in a large area, a yield thereof is difficult to be increased.